Could we do without healing Potency?

[Jaelommiss]

Neither are the oGCDs in most cases. There is basically no interaction between 90% of the abilities in a healer's kit, be it GCDs or oGCDs and oGCDs mostly boil down to "Restore X amount of HP instantly"

Absolutely this. The only healing abilities I can think of that have depth beyond 'push button, get heal/regen/shield' are Plenary and Horoscope. Maybe Earthly Star and Excog if we count special trigger conditions as a type of complexity.